Note: Phylogenetic position of rare human mycoplasmas, Mycoplasma faucium, M. buccale, M. primatum and M. spermatophilum, based on 16S rRNA gene sequences

Abstract
The nucleotide sequence of the 16S rRNA genes of four rare human mycoplasma species, Mycoplasma faucium, M. buccale, M. primatum and M. spermatophilum, were partially sequenced and compared to published rRNA genes of mycoplasmas to determine their position in the Mollicutes phylogenetic tree. Nucleotide sequence motif and overall similarities allowed positioning of these mycoplasmas in the hominis phylogenetic group, as defined by Weisburg et al. [Weisburg, W. G., Tully, J. G., Rose, D. L. & 9 other authors (1989). J Bacteriol 171, 6455--6467]. Furthermore, these mycoplasmas could be clustered into two different subdivisions of the hominis group: (i) M. faucium and M. buccale were found to be included in the M. fermentans subdivision, and (ii) M. primatum and M. spermatophilum were included in the M. hominis one. Variable regions of the 16S rRNA genes were used to determine specific PCR primers to detect and identify M. faucium.